In fuel cells a fuel gas and an oxidant gas are used to produce an electrical current. The fuel gas is supplied to an anode chamber in which is located an anode electrode, and the oxidant gas is supplied to a cathode chamber in which is located a cathode electrode. An electrolyte is located between the anode and cathode electrodes. The fuel gas is oxidised at the anode to produce ions and free electrons. The free electrons are supplied to one terminal of the fuel cell, and the other terminal supplies free electrons to the cathode to reduce the oxidant gas. The ions pass through the electrolyte to react with the oxidant.
In one known type of fuel cell hydrogen is used as the fuel gas and oxygen is used as the oxidant gas. This type of fuel cell comprises an anode chamber in which is located an anode electrode, a cathode chamber in which is located a cathode electrode and an electrolyte which is located between the anode and cathode electrode. Hydrogen is supplied to the anode chamber and oxygen is supplied to the cathode chamber. The electrolyte is typically a solid polymer electrolyte.
In operation water is transported from the anode electrode to the cathode electrode through the solid polymer electrolyte by the action of positive ions passing through the solid polymer electrolyte from the anode electrode to the cathode electrode. Also water is produced by the reaction of the positive hydrogen ion with the oxygen at the cathode electrode. Thus water may collect on the surface of the cathode electrode and prevent the oxygen contacting the cathode electrode and the anode electrode may become dry due to the transportation of water from the anode to the cathode, this leads to a reduction in the operating efficiency of the fuel cell. Heat is also generated when the hydrogen ions combine with the oxygen to produce water.
Therefore there is a requirement for a fuel cell which has a water management system which will prevent, or reduce the amount of, water collecting on the surface of the cathode electrode and prevent the surface of the anode electrode becoming dry. There is also a requirement for a fuel cell which has a heat management system which will dissipate heat from the fuel cell.